Check Your Water Heater's Age

If your gas water heater is more than 10 years old, it may be time to replace it. Use this page as a resource to help identify the age of your water heater so you're prepared.

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Step 1.Find the Label

On your water heater is label with the manufacturer's name, model, serial number, and other technical specifications.

Step 2.Write Down Your Model & Serial Number

Save the model and serial number by writing it down on the sticker the City mailed to you.

Step 3.Use this Guide to Understand its Age

Each manufacturer has a different method to identify a water heater's age. The following are the most common water heaters in use. If you have a different manufacturer, visit their website to learn how to identify the water heater's age.

Rheem

Serial number: MMYYxxxxxx

MM = Month of manufacture

YY = Year of manufacture

Example: 1209D01234, December 2009

AO Smith

Current

Serial number: YYWWxxxxxx

YY = Year of manufacture

WW = Week of manufacture

Example: 203707002601001, early September 2020

Pre-2008

Serial Number: xAYYxxxxxx

Second digit = Month A - N (excluding I), A=Jan, B=Feb, etc.

YY = Year of manufacture

Example: 2C062938405, March 2006

Bradford White

The year is the first letter and month is the second. Use the table below to determine age noting these water heaters manufactured 20 years apart have the same letter designation.

Serial number: YMxxxxxx

Example: HK16433183, October 2011

Production Year

A = 2004 or 2024

B = 2005 or 2025

C = 2006 or 2026

D = 2007 or 2027

E = 2008 or 2028

F = 2009 or 2029

G = 2010 or 2030

H = 2011 or 2031

J = 2012 or 2032

K = 2013 or 2033

L = 2014 or 2034

M = 2015 or 2035

N = 2016 or 2036

P = 2017 or 2037

S = 2018 or 2038

T = 2019 or 2039

W = 2020 or 2040

X = 2021 or 2041

Y = 2022 or 2042

Z = 2023 or 2043
Production Month
A = January
B = February
C = March
D = April
E = May
F = June
 G = July
H = August
J = September
K = October
L = November
M = December

Step 4.Write Down the Manufacture Date

On your water heater's sticker, write down the manufacture date so you know when it comes time to replace the water heater. Don't be without hot water. Contact us when the time comes and/or you're ready to make the switch. The City has programs offering technical and financial support to help.
sample view of the water heater age write in on the mailed sticker from the city of Palo Alto

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Switch to a Heat Pump Water Heater

Don't wait until it's too late, switch now!

While this guide will help you know when to expect your gas water heater's end of life, it's better not to wait and switch. Prevent an emergency situation where you're out of hot water, and make the switch now.

Switch to a Heat Pump Water Heater

Get Advice

The City's experts can help guide you with questions you may have about your water heater, switching to a heat pump, financial questions and more.

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